Wheat flour, which forms the basis for leavened baked products such as conventional breads, comprises mainly starch and gluten. The gluten component is acknowledged as being the major factor in the retention of gas developed within the dough, adequate gas production and retention being critical to the production of an acceptable product. The gluten functions by undergoing hydration and subsequently forming a network or matrix which encompasses the other components especially the starch component. In order to fulfill this role the gluten must be vital, i.e., not denatured and in many ways wheat gluten is exceptional in that this property is not possessed by many other vegetable proteins, for example, soybean protein. In addition to the above role, gluten also constitutes a valuable source of protein. Gluten and other proteins, such as soybean protein referred to above, are also added to flour doughs to supplement the indigenous or native protein content of the flour. However, supplemental vital gluten is able to fulfill the dual roles referred to above, whereas other supplemental proteins merely increase the protein content in the product. The ability of the supplemental gluten to enter into the protein matrix created by the indigenous gluten is extremely desirable leading as it does to a product having an improved structure, crumb, volume and firmness. It will be appreciated therefore, that maintaining and, if possible, increasing the vitality of the gluten is extremely important because of the resulting advantages which are obtained.
Gluten is also used in the production of many food products where its unique ability to modify the structure and texture of various food materials may be exploited. Examples of such products are simulated meat products (for consumption both by humans and pets), breakfast cereals, textured vegetable protein and simulated cheese products. However, some difficulties are encountered when dispersing gluten throughout many food systems and these restrict its more widespread use in such applications. Dispersibility of gluten depends in part on its moisture-imbibing and maleability characteristics and improvement thereof would therefore be highly desirable.
Many methods are known to preserve and/or improve the vitality, maleability, etc., of normal vital gluten: one such method is described in U.S. Pat. No. 3,704,131. However, the prior art methods leave something to be desired.
Gums such as carrageenan, locust bean gum and arabic gum have been used in many food products, for example, in bread as anti-staling agents. (Refer to the Handbook of Food Additives, 2nd Edition, page 325, at page 348.) However, attempts to use xanthan gum in conventional doughs were found to be unsuccessful, the resulting products being inferior to those produced from conventional doughs. Also, use of a mixture of xanthan gum and gluten in combination with starch had the same effect, namely the resulting baked products were inferior to those products using either component alone. (Refer to the article entitled "Engineered Foods of the Future: Baked Goods Fortified with Vegetable Protein" by D. D. Christainson [Northern Regional Research Laboratory, U.S. Dept. of Agr., Peoria, Illinois] dated Mar. 23, 1976.)
Additionally, there have been many attempts to produce a bread-like product which does not require or rely on gluten. This would make "bread" available to persons who are not able to digest gluten-containing products, and would also enable bread-like products to be manufactured in locations where a ready supply of wheat flour itself, or the necessary vital gluten, is not available. Much effort has been expended in recent times to utilize the microbially-produced gums to fulfill the role of gluten in bread-like products. As reference to the article by Christainson shows the research has to some extent been successful. It was found that a combination of xanthan gum and starch per se could be formed into a dough which gives a product very similar to bread produced using conventional doughs. Since the presence of free or gelatinized starch is apparently essential it is believed that the xanthan gum reacts with the starch and thereby forms a matrix similar to that previously obtainable only with gluten. Moreover, it is possible to load the matrix so-formed with up to about 22 percent protein for example, in the form of soy isolate. However, as mentioned above and reported at page 4 of the Christainson article referred to previously, it was considered that xanthan gum had only deleterious effects when added to conventional flour doughs containing indigenous (gluten) protein.